1. Field of the Invention
This invention relates in general to communication systems and in particular to systems for communication of location sensitive information.
2. Description of the Related Art
Short range wireless communication and personal area networking capability will soon proliferate in common household products as well as mobile business products. Currently many products that have wireless capability are incompatible. Short range wireless local area network (WLAN) protocols such as Bluetooth, HomeRF, and IEEE 802.11 provide an avenue towards compatibility. These short range WLAN protocols operate at lower power and over shorter distances. Further, these short range WLAN protocols generally use unlicensed spectrum and require minimal coordination with the wide area communication protocol also used by the device such as the Global System for Mobile Communications (GSM) and ReFLEX™ protocols.
Short range wireless communication can be, for example, provided using an Infrared Data Association (IrDA) communication standard. IrDA is a point-to-point, narrow angle (30 degree cone), ad-hoc data transmission standard designed to operate over a distance of zero (0) to one (1) meter and at speeds of ninety six hundred (9600) bits per second to sixteen (16) Mega bits per second. Similarly, the short range communication can be provided using a Bluetooth communication standard. Bluetooth is a short range, point-to-multipoint voice and data transfer standard designed to operate over a nominal distance of ten (10) centimeters to ten (10) meters, which can be extended to one hundred (100) meters by increasing transmit power. Bluetooth operates in the 2.4 Gigahertz radio frequency range.
Short range WLAN protocols such as IrDA and Bluetooth technology allow for the replacement of the many proprietary cables that connect one device to another with one universal short range radio link. For example, short range WLAN protocol technology can replace the cumbersome cables used today to connect between a laptop computer and a cellular telephone, between printers, personal digital assistants, desktops, fax machines, keyboards, and joysticks, or between other similar digital devices. Further, appliances such as refrigerators, microwave ovens, dishwashers, laundry washers & dryers, stereos, televisions, digital video disks, video games, lighting, irrigation, cooling and heating systems can also take advantage of such short range radio links.
Potential applications of low power, short range protocols include wireless connection of peripheral devices, high-speed data transfers to desktop computers and wireline networks, and establishment of short range WLANs by the sharing of the same channel between similar wireless communication devices. Typically, in a short range WLAN, one of the devices functions as the master while the others function as slaves. For example, in a Bluetooth system, up to seven active slaves can exist in a WLAN, while many more can remain locked to the same master in a so-called parked state. These parked units cannot be active on the channel, but remain synchronized to the master. The master always controls the channel access for both the active and the parked units. The master in a Bluetooth system controls the traffic across the channel using a polling scheme. Once a short range WLAN has been established, master-slave roles can be exchanged. To avoid collisions, communication between two slaves can only be accomplished through the master unit.
Many short range WLANs such as the Bluetooth system support scatternets. A scatternet is the combination of two or more networks with overlapping coverage area. Each network can only have one master. However, a master in one network can participate as a slave in another and slaves can also participate in different networks on a time division multiplex basis. Networks within a scatternet are not time or frequency synchronized. Each network uses its own hopping sequence.
Recently some portable devices incorporate the capability to determine device location. For example, a wireless communication system can use direction finding equipment at each base station site in order to fix the location of the portable device. The current device location is computed by triangulation when two or more transmitter base stations receive the same signal. Thus, when two or more transmitter base stations cannot receive the same signal the location of the portable device cannot be accurately determined. In addition, even when the two or more base stations can receive the same signal the system still has limited ability to accurately determine the location of the portable device due to the random propagations signaling paths between the portable device and the base station receivers.
Similarly, the portable device can include a Global Positioning System (GPS) receiver for determining its current location. The Global Positioning System (GPS) is a worldwide radio-navigation system formed from a constellation of twenty four (24) satellites and their ground stations. GPS uses these “man-made stars” as reference points to calculate positions accurate to a matter of meters. The GPS receiver uses the satellites in space as reference points for locations here on earth. The GPS receiver measures distance using the travel time of radio signals. The GPS receiver has very accurate timing to measure travel time. Along with distance, the GPS receiver knows exactly where the satellites are in space. Finally, the GPS receiver corrects for any delays the signal experiences as it travels through the atmosphere. Disadvantageous to the portable device is the added cost and size requirements associated with the inclusion of on-board location determining components
Typically, a short range WLAN determines the location of a portable device by pre-knowledge of the location of a fixed smart network access point or the knowledge of the location limitations of the short range WLAN network that the portable device is utilizing to communicate through. Therefore, the short range WLAN does not need to request the present location from the portable device to provide location sensitive information. For example, the short range WLAN can be a private network with firewalls that have predetermined smart network access points located in an office building. Therefore, getting information with regards to vending machine locations or directions to a meeting room within the building from a current device location can be done within such a private network without the portable device having knowledge of its current location.
One disadvantage of today's communication systems is that the local area communication system alone has the location data. Therefore, only location sensitive information requested through that local area communication system can be provided. The portable device does not have the capability of receiving location sensitive information independent of the local area communication system. Disadvantageously to the device user, the short range WLAN could be void of any location sensitive information for the surrounding area, which otherwise could be provided by a wide area communication system. For example, although directions to a meeting room from an office can be given from the short range WLAN within an office building, the daily lunch specials and directions to the local seafood restaurant may not be available to be retrieved from that same short range WLAN located behind the firewall.
Portable devices that do not have on-board location determining capability either cannot use location sensitive software applications or require a user to enter the location data manually. (i.e.: by entering a street address and city, or a zip code). For example, this lack of on-board location capability can be due to either the absence of a hardware or software solution or can be due to the inability to access information required by the solution to enable location determination. Manual entry of location data can be problematic, especially when the user has traveled away from his home geographic area.
Dedicated short range WLAN devices typically contain a single method of communication capabilities used to communicate within the short range WLAN. These devices probably do not need to know their location as the network from which they can receive information can have accurate knowledge of where they are located. Therefore, it would be inefficient use of the short range WLAN bandwidth to provide such devices with their current location, as it may not be able to be used by the device.
What is needed is a system and method for facilitating the identification and communication of location sensitive information for a portable device that has multiple communication methods without requiring the use by the portable device of on-board location determining capability. (For example, when the portable device on-board location determining capability is not available due to either the absence of a hardware or software solution or due to the inability to access information required by the solution to enable location determination.) Further, what is needed is an efficient low cost system and method for location sensitive information access independent of a particular local area communication network or system.